Do you know of any references or information of salt causing low blood pressure? A family member who stopped taking salt developed high blood pressure, so he added salt back into his diet and his blood pressure lowered to normal ranges.

I don't have any references off hand. Although it has been known for a long time that only about 10% of hypertensive people are sodium sensitive and that withholding sodium in people not sodium sensitive can cause the blood pressure to go up. Most likely this is going to be from the beneficial effects of salt on the adrenals, which play a major role in maintaining proper blood pressure.

Now when he takes salt, his blood pressure drops too low..in the low ninties over mid fifties range.

Also check what kind of salt he is using. If it is high in potassium this will lower the blood pressure. Potassium chloride is sold as a substitute for sodium chloride for people trying to avoid sodium.

Also, what would you recommend for helping to raise blood pressure. Licorice root seems to be one herb that is good for that.

Licorice root is good as well as other adaptogens seaweeds, and vitamin C and pantothenic acid. These help to strengthen the adrenal glands, which in turn help to regulate the blood pressure.